Agricultural baler with improved needle coupling device

Abstract

A baler including a bale chamber; a plunger configured to compress crop material in the bale chamber in order to form a bale; a needle yoke with a plurality of needles configured to deliver twine through the bale chamber; a plurality of knotters configured to receive the twine from the plurality of needles; a bale length measurement and trigger device configured to measure the length of the bale in the bale chamber and to generate a trigger when a predetermined length is reached; a driving shaft located above the bale chamber and extending in a traverse direction of the baler; a needle coupling device between the driving shaft and the needle yoke, the needle coupling device being configured for moving the needle yoke from a rest position to a twine delivery position and back, when the bale length measurement and trigger device generates a trigger.

The invention claimed is: 
     
       1. A baler comprising:
 a bale chamber; 
 a plunger configured to compress crop material in the bale chamber in order to form a bale; 
 a needle yoke comprising a plurality of needles configured to deliver twine through the bale chamber; 
 a plurality of knotters configured to receive the twine from the plurality of needles; 
 a bale length measurement and trigger device configured to measure a length of the bale in the bale chamber and to generate a trigger when a predetermined length is reached; 
 a driving shaft located above the bale chamber and extending in a traverse direction of the baler; 
 a gear box configured to continuously rotate the driving shaft when the baler is in operation; and 
 a needle coupling device between the driving shaft and the needle yoke, the needle coupling device configured for moving the needle yoke from a rest position to a twine delivery position and back when the bale length measurement and trigger device generates a trigger, the needle coupling device comprising:
 a crank arm attached to the driving shaft and co-rotating with the driving shaft; and 
 a plurality of coupling members positioned between the crank arm and the needle yoke, the plurality of coupling members configured for establishing an uncoupling and a coupling between the crank arm and the needle yoke when the bale length measurement and trigger device generates a trigger. 
 
 
     
     
       2. The baler of  claim 1 , wherein the needle yoke further comprises:
 two needle support arms each having a first end and a second end; and 
 a needle carrying rod extending in a transverse direction of the baler and carrying the plurality of needles, 
 wherein the needle carrying rod is mounted between the first ends of the needle support arms, and 
 wherein the second ends of the needle support arms are pivotally mounted around a fixed pivot axis extending in the transverse direction of the baler. 
 
     
     
       3. The baler of  claim 2 , wherein the plurality of coupling members comprises:
 a drive rod having a first end pivotally connected to the crank arm and a second end; 
 a connection member pivotally mounted at a first location around a first fixed pivot axis extending in a transverse direction of the baler, and pivotally connected at a second location to the second end of the drive rod, such that in operation the connection member is swung back and forward around the first fixed pivot axis by the drive rod; and 
 a coupler configured to couple the connection member to the needle yoke upon receipt of a trigger, 
 wherein the first fixed pivot axis of the connection member corresponds with the fixed pivot axis of the second ends of the needle support arms. 
 
     
     
       4. The baler of  claim 1 , wherein the plurality of coupling members comprises:
 a drive rod having a first end pivotally connected to the crank arm and a second end; 
 a connection member pivotally mounted at a first location around a first fixed pivot axis extending in a transverse direction of the baler, and pivotally connected at a second location to the second end of the drive rod, such that in operation the connection member is swung back- and forward around the first fixed pivot axis by the drive rod; and 
 a coupler configured to couple the connection member to the needle yoke upon receipt of the trigger. 
 
     
     
       5. The baler of  claim 4 , wherein the coupler is a hook member which is pivotally attached to the needle yoke and which is positionable in a first coupling position in which the connection member engages the hook member during swinging and in a second uncoupling position in which the connection member does not engage the hook member during swinging, and wherein the bale length measurement and trigger device is further configured to generate a first trigger which positions the hook member in the first coupling position when a predetermined length is reached, and a second trigger which positions the hook member in the second uncoupling position. 
     
     
       6. The baler of  claim 5 , further comprising a trigger coupling device between the connection member and the bale length measurement and trigger device, the trigger coupling device configured to cause the bale length measurement and trigger device to generate the second trigger. 
     
     
       7. The baler of  claim 5 , wherein the bale length measurement and trigger device comprises:
 a star wheel configured to rotate as the bale in the bale chamber moves in a longitudinal direction of the baler; and 
 a linkage assembly coupled to the star wheel, the linkage assembly comprising a pivotally mounted trigger arm arranged to trigger a movement of the coupler from an uncoupled position to a coupled position and back. 
 
     
     
       8. The baler of  claim 1 , further comprising a needle holding device configured to hold the needle yoke in the rest position and to allow the needle yoke to be released when movement from the rest position to the twine delivery position and back is required. 
     
     
       9. The baler of  claim 1 , further comprising:
 a driveable knotter shaft coupled to the plurality of knotters; and 
 a knotter coupling device between the driving shaft and the driveable knotter shaft, the knotter coupling device configured to couple the driving shaft to the driveable knotter shaft based on a position of the needle yoke. 
 
     
     
       10. The baler of  claim 9 , wherein the needle yoke further comprises:
 two needle support arms each having a first end and a second end; and 
 a needle carrying rod extending in a transverse direction of the baler and carrying the plurality of needles, 
 wherein the needle carrying rod is mounted between the first ends of the needle support arms, 
 wherein the second ends of the needle support arms are pivotally mounted around a fixed pivot axis extending in the transverse direction of the baler, and 
 wherein the knotter coupling device comprises:
 a clutch between the driving shaft and the knotter shaft: and 
 a rod assembly comprising a rod connected to at least one of the two needle support arms of the needle yoke, the rod assembly configured for engaging the clutch such that the driving shaft is coupled to the knotter shaft. 
 
 
     
     
       11. The baler of  claim 9 , wherein each knotter comprises:
 a knotter disc secured to the driveable knotter shaft; and 
 a billhook. 
 
     
     
       12. The baler of  claim 11 , wherein for each knotter:
 the knotter disc comprises a first gear stretch, a second gear stretch, and a third gear stretch, 
 the billhook comprises a billhook gear configured for cooperating with the first, second, and third gear stretches, and 
 the first, second, and third gear stretches of the knotter disc are circumferentially spaced in order for the billhook to perform a first rotation during a first knot forming cycle, a second rotation during a second knot forming cycle, and a third rotation. 
 
     
     
       13. The baler of  claim 12 , wherein for each knotter:
 the each knotter further comprises a twine disc configured for holding strands of twine in position for engagement by the billhook during rotation of the billhook, 
 the knotter disc comprises a plurality of gear sections, 
 the twine disc comprises a twine disc gear configured for cooperating with the plurality of gear sections of the knotter disc, 
 the plurality of gear sections are circumferentially spaced in order for the twine disc to perform a first rotation during the first knot forming cycle and a second rotation which is longer than the first rotation during the second knot forming cycle, and 
 the each knotter further comprises:
 a swing arm with a knife blade for severing strands in response to a swinging movement of the swing arm, the swing arm comprising a cam adapted for following a cam track of the knotter disc, the cam track being adapted for performing a first swing during the first rotation and a second swing during the second and third rotation; and 
 a stripping part for stripping of a knot off of the billhook during the swinging movement of the swing arm. 
 
 
     
     
       14. A baler comprising:
 a bale chamber; 
 a plunger configured to compress crop material in the bale chamber in order to form a bale; 
 a needle yoke comprising a plurality of needles configured to deliver twine through the bale chamber; 
 a plurality of knotters configured to receive the twine from the plurality of needles; 
 a bale length measurement and trigger device configured to measure a length of the bale in the bale chamber and to generate a trigger when a predetermined length is reached; 
 a driving shaft located above the bale chamber and extending in a traverse direction of the baler; and 
 a needle coupling device between the driving shaft and the needle yoke, the needle coupling device comprising:
 a crank arm attached to the driving shaft and co-rotating with the driving shaft; and 
 a plurality of coupling members between the crank arm and the needle yoke, the plurality of coupling members configured for being brought from an uncoupled position in which the crank arm is not connected to the needle yoke to a coupled position in which the crank arm and the needle yoke are coupled when the bale length measurement and trigger device generates a trigger. 
 
 
     
     
       15. The baler of  claim 14 , further comprising a gear box coupled with the driving shaft, the gear box configured to continuously rotate the driving shaft when the baler is in operation. 
     
     
       16. The baler of  claim 14 , wherein the plurality of coupling members comprises:
 a drive rod having a first end pivotally connected to the crank arm and a second end; 
 a connection member pivotally mounted at a first location around a first fixed pivot axis extending in a transverse direction of the baler, and pivotally connected at a second location to the second end of the drive rod such that, in operation the connection member is swung back- and forward around the fixed pivot axis by the drive rod; and 
 a coupler configured to couple the connection member to the needle yoke upon receipt of the trigger. 
 
     
     
       17. The baler of  claim 16 , wherein the first fixed pivot axis of the connection member corresponds with the fixed pivot axis of the second ends of the needle support arms. 
     
     
       18. The baler of  claim 16 , wherein the coupler is a hook member which is pivotally attached to the needle yoke and which is positionable in a first coupling position in which the connection member engages the hook member during swinging and in a second uncoupling position in which the connection member does not engage the hook member during swinging, and wherein the bale length measurement and trigger device is further configured to generate a first trigger which positions the hook member in the first coupling position when a predetermined length is reached, and a second trigger which positions the hook member in the second uncoupling position. 
     
     
       19. The baler of  claim 14 , wherein the needle yoke comprises:
 two needle support arms each having a first end and a second end; and 
 a needle carrying rod extending in a transverse direction of the baler and carrying the plurality of needles, 
 wherein the needle carrying rod is mounted between the first ends of the needle support arms, and 
 wherein the second ends of the needle support arms are pivotally mounted around a fixed pivot axis extending in the transverse direction of the baler. 
 
     
     
       20. A baler comprising:
 a bale chamber; 
 a plunger configured to compress crop material in the bale chamber in order to form a bale; 
 a needle yoke comprising:
 a plurality of needles configured to deliver twine through the bale chamber; 
 two needle support arms each having a first end and a second end, the second ends pivotally mounted around a fixed pivot axis extending in a transverse direction of the baler; and 
 a needle carrying rod extending in the transverse direction of the baler and carrying the plurality of needles, the needle carrying rod mounted between the first ends of the needle support arms; 
 
 a plurality of knotters configured to receive the twine from the plurality of needles; 
 a bale length measurement and trigger device configured to measure a length of the bale in the bale chamber and to generate a trigger when a predetermined length is reached; 
 a driving shaft located above the bale chamber and extending in a traverse direction of the baler; 
 a needle coupling device positioned between the driving shaft and the needle yoke and the needle coupling device configured for establishing an uncoupling and a coupling between the driving shaft and the needle yoke, the needle coupling device configured for moving the needle yoke from a rest position to a twine delivery position and back, when the bale length measurement and trigger device generates a trigger; 
 a driveable knotter shaft coupled to the plurality of knotters; and 
 a knotter coupling device between the driving shaft and the driveable knotter shaft, the knotter coupling device configured to couple the driving shaft to the driveable knotter shaft based on a position of the needle yoke, the knotter coupling device comprising:
 a clutch between the driving shaft and the driveable knotter shaft; and 
 a rod assembly comprising a rod connected to at least one of the two needle support arms of the needle yoke, the rod assembly configured for engaging the clutch such that the driving shaft is coupled to the driveable knotter shaft.